My boyfriend and I have been dating for more than 1 and a half years. In the past few months everything went downhill. All of a sudden, I changed into a selfish, arrogant, inconsiderate girlfriend. My boyfriend, who is way more mature than I am, put up with all of that for the longest time even though he got extremely hurt in the process. Now it is to the point he wanted to break up with me and is completely heart broken. I begged him to give me one last chance and he gave me another chance, but he did tell me that he has no guarantee that our relationship will ever be the same again to the point where he loves me completely. And in the past, we were absolutely serious about each other. But now, he says even if I do change and prove that I am a good girlfriend, he doesn't know if he wants a future with me. So what is the best thing for us to do? We have agreed that if things don't work out, we will break up. He is the kind of guy who never gives up on anything, but he told me that I am the first thing in his entire life that he ever gave up on trying anymore because he had to put up with me for so long. What should I do?